Fluid end with curved internal cavity profile

ABSTRACT

A fluid end assembly includes a fluid end and a plurality of valve assemblies each located within a cavity that has curved internal profiles. The curved internal profiles of the cavities are concaved outward. A plunger is included to provide variations in pressure within the fluid end so as to facilitate movement of the working fluid. A discharge plug is included in communication with the fluid end. The discharge plug may include a curved profile along an inner surface that corresponds with one of the cavities therein. A suction plug is releasably coupled to the fluid end and includes a curved profile along an inner surface. The suction plug also includes a recess for acceptance of a spring retainer. The spring retainer is included to support a suction valve assembly.

CLAIM OF PRIORITY

This application claims the benefit of U.S. Provisional Application No.62/555,546, filed 7 Sep. 2017. The information contained therein ishereby incorporated by reference.

BACKGROUND 1. Field of the Invention

The present application relates generally to a reciprocating pump, andin particular to a fluid end having a curved internal cavity profile forthe reduction of turbulent flow and cavitation in the system.

2. Description of Related Art

It is difficult to economically produce hydrocarbons from lowpermeability reservoir rocks. Oil and gas production rates are oftenboosted by hydraulic fracturing, a technique that increases rockpermeability by opening channels through which hydrocarbons can flow torecovery wells. During hydraulic fracturing, a fluid is pumped into theearth under high pressure (sometimes as high as 50,000 PSI) where itenters a reservoir rock and cracks or fractures it. Large quantities ofproppants are carried in suspension by the fluid into the fractures.When the pressure is released, the fractures partially close on theproppants, leaving channels for oil and gas to flow.

Specialized pumps are used to deliver fracture fluids at sufficientlyhigh rates and pressures to complete a hydraulic fracturing procedure or“frac job.” These pumps are usually provided with fluid ends having bothreciprocating plungers that place fluids under pressure and valves thatcontrol fluid flow to and from the plungers. Fluid ends have many partsthat are releasably fastened to one another so that they can be repairedor replaced. These fluid ends experience large amounts of internalstresses from turbulent flows and cavitation as the fracture fluids arepassed through. Conventional designs where linear wall profiles andedges are prevalent contribute to this. By the nature of its operation areciprocating pump or fluid end induces turbulent flow and cavitationinto the system. These effects are detrimental to the whole pumpingsystem. These stresses reduce the life of the fluid end and its internalcomponents.

Although great strides have been made with respect to fluid end design,considerable shortcomings remain. An improved fluid end is needed thatminimizes the internal stresses on the fluid end during operation.

SUMMARY OF THE INVENTION

It is an object of the present application to provide a fluid endassembly that reduces internal stresses through the incorporation ofcurved internal cavity profiles. This design is to reduce the internalstresses on the fluid end in operation by optimizing the internalprofile of the cavities to produce a more laminar flow of the proppant.The addition of these profiles to the internal cavities and componentsmitigate the turbulent and cavitation present in the proppant.

It is a further object of the present application that the profiles ofthe suction port and discharge port in the fluid end are curved andconsist of one or more radiuses. The radiuses are set at differentdiameters. The discharge plug may also include a curved profile to matchthat of the curved profile in the discharge cavity of the fluid end. Thedischarge curve profile in the discharge plug is profiled to continuethe arc from the fluid end curved discharge port profile.

The suction plug is composed of a single member wherein the traditionalplug and nut are combined together. The inner surface of the suctionplug has a radiused profile. The discharge plug and the suction plughave mating faces and an adjacent recessed seal. As the plugs arethreaded into location, the seal rides the chamfer thereby compressingthe seal to the conforming diameter. The intersection of the chamferstart point and the seal groove is the same as the seal diameter.Therefore, no extrusion gap is created and the seal can not extrude soas to increase the feature life. Additionally, when fully seated, a gapis always present above the mating surfaces and seal.

Furthermore, it is a further object to provide a curved profile in thesuction cavity of the fluid end. A spring retainer is seated in thesuction cavity to hold the spring that operates the valve. A flat faceis machined into the curved profile of the suction cavity to align thespring retainer in position and prevent the spring retainer from movingthrough the bore cavity. The suction plug includes the radiused featureswhich help to guide the spring retainer into position during assemblyand stops it from rotating circumferentially relative to the borediameter.

Ultimately the invention may take many embodiments. This assemblyovercomes the disadvantages inherent in the prior art. The moreimportant features of the assembly have thus been outlined in order thatthe more detailed description that follows may be better understood andto ensure that the present contribution to the art is appreciated.Additional features of the system will be described hereinafter and willform the subject matter of the claims that follow.

Many objects of the present assembly will appear from the followingdescription and appended claims, reference being made to theaccompanying drawings forming a part of this specification wherein likereference characters designate corresponding parts in the several views.

Before explaining at least one embodiment of the system in detail, it isto be understood that the assembly is not limited in its application tothe details of construction and the arrangements of the components setforth in the following description or illustrated in the drawings. Theassembly is capable of other embodiments and of being practiced andcarried out in various ways. Also it is to be understood that thephraseology and terminology employed herein are for the purpose ofdescription and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception,upon which this disclosure is based, may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the various purposes of the present system. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present system.

DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the application are setforth in the appended claims. However, the application itself, as wellas a preferred mode of use, and further objectives and advantagesthereof, will best be understood by reference to the following detaileddescription when read in conjunction with the accompanying drawings,wherein:

FIG. 1 is a perspective view of a fluid end assembly according to anembodiment of the present application.

FIG. 2 is a side view of the fluid end assembly of FIG. 1.

FIG. 3 is a section view of the fluid end assembly of FIG. 1.

FIG. 4 is an enlarged partial section view of the fluid end assembly ofFIG. 3.

FIG. 5 is an enlarged partial section view of the fluid end assembly ofFIG. 3.

FIG. 6 is an enlarged partial section view of the fluid end assembly ofFIG. 3.

While the assembly and method of the present application is susceptibleto various modifications and alternative forms, specific embodimentsthereof have been shown by way of example in the drawings and are hereindescribed in detail. It should be understood, however, that thedescription herein of specific embodiments is not intended to limit theapplication to the particular embodiment disclosed, but on the contrary,the intention is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the process of thepresent application as defined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Illustrative embodiments of the preferred embodiment are describedbelow. In the interest of clarity, not all features of an actualimplementation are described in this specification. It will of course beappreciated that in the development of any such actual embodiment,numerous implementation-specific decisions must be made to achieve thedeveloper's specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

In the specification, reference may be made to the spatial relationshipsbetween various components and to the spatial orientation of variousaspects of components as the devices are depicted in the attacheddrawings. However, as will be recognized by those skilled in the artafter a complete reading of the present application, the devices,members, apparatuses, etc. described herein may be positioned in anydesired orientation. Thus, the use of terms to describe a spatialrelationship between various components or to describe the spatialorientation of aspects of such components should be understood todescribe a relative relationship between the components or a spatialorientation of aspects of such components, respectively, as the assemblydescribed herein may be oriented in any desired direction.

The assembly and method in accordance with the present applicationovercomes one or more of the above-discussed problems commonlyassociated with conventional fluid ends by reducing the internalstresses through the incorporation of curved internal cavity profiles.This design is configured to reduce the internal stresses on the fluidend during operation by optimizing the internal profile of the cavitiesto produce a more laminar flow of the proppant. The addition of theseprofiles to the internal cavities and components mitigate the turbulentand cavitation present in the proppant. These and other unique featuresof the device are discussed below and illustrated in the accompanyingdrawings.

The assembly and method will be understood, both as to its structure andoperation, from the accompanying drawings, taken in conjunction with theaccompanying description. Several embodiments of the assembly may bepresented herein. It should be understood that various components,parts, and features of the different embodiments may be combinedtogether and/or interchanged with one another, all of which are withinthe scope of the present application, even though not all variations andparticular embodiments are shown in the drawings. It should also beunderstood that the mixing and matching of features, elements, and/orfunctions between various embodiments is expressly contemplated hereinso that one of ordinary skill in the art would appreciate from thisdisclosure that the features, elements, and/or functions of oneembodiment may be incorporated into another embodiment as appropriate,unless otherwise described.

The assembly and method of the present application is illustrated in theassociated drawings. The assembly includes a fluid end with internalcurved cavity profiles. The fluid end includes a plunger bore having acurved profile, a suction cavity with a curved internal profile, and adischarge cavity with a curved internal profile. A suction valve islocated in the suction cavity. The suction cavity is concaved outwardsuch that the diameter of the suction cavity is largest about itscenter. A discharge valve is located in the discharge cavity. Thedischarge cavity is concaved outward such that the diameter of thedischarge cavity is largest about its center. A discharge valve may belocated in communication with the discharge valve and the dischargecavity. The discharge plug may include a curved profile adjacent thecavity walls. The profile may be configured to match the curved diameterof the discharge cavity.

The assembly may also include a suction plug as a singular member thatreleasably communicates with the fluid end and is concentric with theplunger. The suction plug may have one or more curved profiles along aninner surface. The suction plug also includes a groove for acceptance ofa spring retainer in communication with the suction valve. Additionalfeatures and functions of the device are illustrated and discussedbelow.

Referring now to the Figures wherein like reference characters identifycorresponding or similar elements in form and function throughout theseveral views. The following Figures describe the assembly of thepresent application and its associated features. With reference now tothe Figures, an embodiment of the modular observation assembly andmethod of use are herein described. It should be noted that the articles“a”, “an”, and “the”, as used in this specification, include pluralreferents unless the content clearly dictates otherwise.

Referring now to FIGS. 1 and 2 in the drawings, a perspective view andside view of a fluid end assembly 101 is illustrated. Assembly 101 isconfigured to provide a reduction in internal stresses through theincorporation of curved internal cavity profiles which will beillustrated below. The curved internal cavity profiles may be providedthrough the fluid end and any of the associated plugs and valves.Assembly 101 includes a fluid end 103. Fluid end 103 includes a numberof internal cavities and surfaces used in the movement of proppant. Thesurfaces of the cavities are curved to facilitate reduced stress. Thesewill be depicted in the following figures. As seen in FIG. 1, adischarge plug 107 and a suction plug 105 are shown engaged with fluidend 103. A gauge port 104 is shown in communication with discharge plug107. For purposes herein, discussion will be related to the combinedplug 107 and gauge port 104 as a single discharge plug 107, as plug 107may be used singly or as a combination with gauge 104.

Referring now also to FIG. 3 in the drawings, a section view of fluidend assembly 101 is illustrated. Internally, fluid end assembly 101includes a plunger 109, a suction valve assembly 111, a discharge valveassembly 113, a suction plug 105, and discharge plug 107 (i.e. combinedgauge 104 and plug 107). Plunger 109 passes through a plunger bore 117.Plunger bore 117 extends from surface 119 of fluid end 103 internally tosuction plug 105. Suction valve assembly 111 resides in a suction cavity121. Cavity 121 is adjacent to and in communication with plunger bore117. Discharge valve assembly 113 resides in a discharge cavity 123.Cavity 123 is adjacent to and in communication with plunger bore 117 aswell.

Plunger bore 117 has a varied internal diameter. Plunger bore 117extends linearly away from surface 119 and then expands away from itsaxis and plunger 109 near the distal end of plunger 109. Diameter 125 aof plunger bore 117 is smaller than diameter 125 b of plunger bore. Thesurface of plunger bore between the diameters may be linear or mayinclude a curved surface (i.e. be radiused). Plunger bore 117 mayinclude one or more radiused curves along the curved surface wherein thecurves are joined tangentially to one another.

Discharge cavity 123 and suction cavity 121 are shown in FIG. 3. Thewalls of each cavity are shown as nonlinear, whereas the walls areradiused outward such that the diameter of the cavity is widest awayfrom the upper and lower ends. The walls of cavity 123 and 121 mayinclude a plurality of radiused curves joined together tangentially suchthat the curve profile is varied. Each curve within the respectivecavity 121 and 123 may be different from an adjacent curve such thattogether they form the curve profile for that particular cavity 121 and123.

Referring now also to FIG. 4 in the drawings, a partial section view offluid end assembly 101 is illustrated. In this view, suction plug 105 ispartially unseated from fluid end 103 for illustrative purposes. As seenin the Figure, plunger 109 is located opposite from suction plug 105.Suction valve assembly 111 is located within cavity 121. Assembly 101may include a spring retainer 127 that spans across the opening ofcavity 121. Retainer 127 is configured to contact one side of spring129, while suction valve assembly 111 is in contact with the opposingside. As plunger 109 reciprocates, the valve in suction valve assembly111 opens and closes, being biased by spring 129. Retainer 127 is seatedagainst the walls of cavity 121. As noted previously, the walls ofcavity 121 consist of one or more curves tangentially adjacent oneanother to form a curved profile 131. Curved profile 131 of cavity 121may include one or more parallel faces 133 tangential to the curveprofile 131 for contact with retainer 127. Face 133 is configured toalign and position spring retainer 127 within cavity 121.

Suction plug 105 is releasably coupled to fluid end 103 and is locatedlinearly in alignment with plunger 109. Suction plug 105 is shown havingan inner surface 135 with a curved profile having one or more curves.Where a plurality of curves exist, a “wave” effect may be realized alongsurface 135. Plug 105 includes a recess 137 along inner surface 135 thatextends inward into plug 105. Recess 137 is configured to accept aportion of spring retainer 127. The outer edges of recess 137 aboutsurface 135 are radiused to facilitate acceptance of retainer 127 andguide retainer 127 into position within recess 137. Recess 137 isconfigured to stop retainer 127 from rotating circumferentially tocavity 121.

Suction plug 105 includes a mating surface 139 that is configured tomate with a fluid end mating surface 140. As seen in FIG. 4, the matingsurfaces are separated as plug 105 is slightly unseated for illustrativepurposes. When fully seated, mating surfaces 139 and 140 are configuredto make full contact. Suction plug 105 also includes a seal groove 141.Seal groove 141 is located below the mating surface 139 and includes aseal 143. Seal 143 defines a diameter. The diameter at the intersectionof the mating surface 139 and seal groove 141 is the same as the sealdiameter to avoid extrusion gap. As seen in FIG. 5, a clearance gap 145exists between plug 105 and fluid end 103 above mating surfaces 139 and140 when plug 105 is fully seated.

Referring now also to FIG. 5 in the drawings, an enlarged section viewof the fluid end assembly of FIG. 3 is illustrated. In FIG. 5, plug 105is fully seated in fluid end 103. Mating surfaces 139 and 140 are incontact. Clearance gap 145 is shown as being maintained. Spring retainer127 is located partially within recess 137. As noted previously, thecurved profile 131 of cavity 121 has one or more radiused curves.Profile 131 expands outward in a concave manner such that diameter 147 ais larger than diameter 147 b

Referring now also to FIG. 6 in the drawings, an enlarged section viewof the fluid end assembly of FIG. 3 is illustrated. Discharge cavity 123is similar to that of suction cavity 121. Cavity 123 has a curvedinternal profile 149 wherein the walls of the profile expand outward ina concave fashion such that the diameter 151 a is larger than thediameter 151 b. The narrowest points of cavity 123 are at the upper andlower most points in the profile 149. Profile 149 may consist of one ormore radiused curves that are joined together tangentially to form theoverall profile 149. The radiused curves may have a different curvediameter.

Discharge plug 107 is configured to engage with and seat against fluidend 103 in a similar manner to that of suction plug 105. Discharge plug107 includes a mating surface 153 that is configured to mate with afluid end mating surface 154. As seen in FIG. 6, the mating surfaces arein contact with one another as plug 107 is shown in a seated position.When fully seated, mating surfaces 153 and 154 are configured to makefull contact. Plug 107 also includes a seal groove 155. Seal groove 155is located below the mating surface 153 and includes a seal 157. Seal157 defines a diameter. The diameter at the intersection of the matingsurface 153 and seal groove 155 is the same as the seal diameter toavoid extrusion gap. A clearance gap 159 exists between plug 107 andfluid end 103 above mating surfaces 153 and 154 when plug 107 is fullyseated.

Plug 107 extends downward into cavity 123. A spring 161 is biasedbetween plug 107 and discharge valve assembly 113, wherein the plug 107and assembly 113 are on opposing ends of cavity 123. As plunger 109reciprocates, pressure within plunger bore 117 pushes open the dischargevalve to permit the discharge of proppant from bore 117. As the valvemoves, spring 161 is actuated between a compressed and relaxed position.Spring 161 contacts surface 163 of plug 107.

Plug 107 has an inner surface 165. Surface 165 may include a nonlinearprofile which extends from a central position in plug 107 toward thewalls of cavity 123. As seen in FIG. 6, the curve profiled of surface165 can be defined between length L1 and length L2. The curve profile ofsurface 165 may be configured to match that of profile 149, such thatthe curved profile of cavity 123 is continued along inner surface 165 ofplug 107.

The current application has many advantages over the prior art includingat least the following: (1) curved internal profiles of the plungerbore, valve cavities, and suction plug surface; (2) reduction ofinternal stresses; (3) singular body suction plug; and (4) minimizedwear.

The particular embodiments disclosed above are illustrative only, as theapplication may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. It is therefore evident that the particularembodiments disclosed above may be altered or modified, and all suchvariations are considered within the scope and spirit of theapplication. Accordingly, the protection sought herein is as set forthin the description. It is apparent that an application with significantadvantages has been described and illustrated. Although the presentapplication is shown in a limited number of forms, it is not limited tojust these forms, but is amenable to various changes and modificationswithout departing from the spirit thereof.

What is claimed is:
 1. A fluid end assembly, comprising: a fluid end; aplunger for reciprocation through a plunger bore in the fluid end; asuction valve located within a suction cavity in the fluid end, thesuction cavity having a curved internal profile; and a discharge valvelocated within a discharge cavity in the fluid end, the discharge cavityhaving a curved internal profile; wherein the curved internal profilesof the suction cavity and the discharge cavity are concaved outward. 2.The assembly of claim 1, wherein the plunger bore is radiused so as toopen or expand away from the plunger adjacent to the suction cavity andthe discharge cavity.
 3. The assembly of claim 1, wherein the plungerbore has a plurality of radiused curves, the plurality of radiusedcurves having at least two different curve diameters joined togethertangentially and cause the diameter of the plunger bore to vary.
 4. Theassembly of claim 1, wherein the suction cavity has a plurality ofradiused curves joined together tangentially.
 5. The assembly of claim4, wherein the plurality of radiused curves in the suction cavity eachhave a different curve diameter.
 6. The assembly of claim 1, wherein thedischarge cavity has a plurality of radiused curves joined togethertangentially.
 7. The assembly of claim 6, wherein the plurality ofradiused curves in the discharge cavity each have a different curvediameter.
 8. The assembly of claim 1, further comprising: a suction plugreleasably coupled to the fluid end and located linearly with theplunger, the suction plug including a curved profile along an innersurface.
 9. The assembly of claim 8, wherein the suction plug includes arecess along the inner surface, the recess being radiused adjacent theinner surface.
 10. The assembly of claim 9, further comprising: a springretainer in communication with the suction valve, the spring retainerconfigured to pass into the recess.
 11. The assembly of claim 8, whereinthe suction plug includes a mating surface and a seal groove, the sealgroove located below the mating surface and includes a seal having adiameter, the mating surface configured to engage a corresponding matingsurface of the fluid end upon installation; and wherein the diameter atthe intersection of the suction plug mating surface and the seal grooveis the same as the seal diameter to avoid extrusion gap.
 12. Theassembly of claim 11, wherein a clearance gap is maintained between thesuction plug and the fluid end above the mating surface.
 13. Theassembly of claim 1, further comprising: a spring retainer incommunication with the suction valve, the suction cavity including oneor more parallel faces tangential to the curved profile of the suctioncavity, the parallel faces configured to align and position the springretainer.
 14. The assembly of claim 1, further comprising: a dischargeplug in communication with both the discharge valve and the dischargecavity, the discharge valve and the discharge plug are on opposing endsof the discharge cavity.
 15. The assembly of claim 14, wherein thedischarge plug includes a discharge plug curve profile adjacent thedischarge cavity.
 16. The assembly of claim 15, wherein the curve of thedischarge plug curve profile is configured to match that of thedischarge cavity curved profile, such that the curved profile of thedischarge cavity is continued along the discharge plug curve profile.17. The assembly of claim 14, wherein the discharge plug includes amating surface and a seal groove, the seal groove located below themating surface and includes a seal having a diameter, the mating surfaceconfigured to engage a corresponding mating surface of the fluid endupon installation; and wherein the diameter at the intersection of thedischarge plug mating surface and the seal groove is the same as theseal diameter to avoid extrusion gap.
 18. The assembly of claim 18,wherein a clearance gap is maintained between the discharge plug and thefluid end above the mating surface.
 19. A fluid end assembly,comprising: a fluid end; a plunger for reciprocation through a plungerbore in the fluid end; a suction valve located within a suction cavityin the fluid end, the suction cavity having a curved internal profile; adischarge valve located within a discharge cavity in the fluid end, thedischarge cavity having a curved internal profile; a discharge plug incommunication with both the discharge valve and the discharge cavity,the discharge valve and the discharge plug are on opposing ends of thedischarge cavity, the discharge plug includes a discharge plug curveprofile adjacent the discharge cavity; a suction plug releasably coupledto the fluid end and located linearly with the plunger, the suction plugincluding a curved profile along an inner surface, the suction plugincludes a recess along the inner surface, the recess being radiusedadjacent the inner surface; and a spring retainer in communication withthe suction valve, the spring retainer configured to pass into therecess of the suction plug; wherein the curved internal profiles of thesuction cavity and the discharge cavity are concaved outward.
 20. Theassembly of claim 19, wherein the curve of the discharge plug curveprofile is configured to match that of the discharge cavity curvedprofile, such that the curved profile of the discharge cavity iscontinued along the discharge plug curve profile.